Method of sealing end closures to containers



Nov. 27, 1951 R. s. CONDON METHOD OF SEALING END CLOSURES TO CONTAINERSOriginal Filed March 9, 1945 3 Sheets-Sheet 1 Ali? /A 74 J0 u .1 I Z6awe/who'l PosE/vr 5 Co/voo/y Nov. 27, 1951 R. s CONDON 2,576,446

METHOD OF SEALING END CLOSUREISYTO CONTAINERS Original Filed March 9,1945 3 Sheets-Sheet 2 /4 if /a 6 24 as 2Q gvwe/wbo'n ROBERT J Co/v0o/vNOV. 27, 1951 s CONDON 2,576,446

METHOD OF SEALING END CLOSURES TO CONTAINERS I Original Filed March 9,1945 3 Sheets-Sheet 5 3mm ADOBE/QT 6. CONDO v Patented Nov. 27, 1951 1METHOD OF SEALING END CLOSURES TO CONTAINERS Robert S. Condon, Rutland,Vt., assignor, by' mesne assignments, to Continental Can Company, NewYork, N. Y., a corporation of New York Original application March 9,1945, Serial No. 581,899. Divided and this application August 29, 1946,Serial No. 693,773

3 Claims. 1

The present invention relates to metal closures for fibre bodiedcontainers, and particularly to the method of sealing a container withsuch a closure.

The present application is a division of my application Serial No.581,899, filed March 9, 1945 (now abandoned).

The sealing of fibre bodied containers presents many problems inasmuchas a leak-proof seal must be obtained, speed of production equal tometal can filling must be maintained, and the cost must be economicallylow. In addition, it is essential that the closure be so made andsecured to the body that the seal will not be broken either by changesof pressure within the container or from shock such as occurs when thecontainer is dropped.

In order to accomplish the foregoing, it is essential that the adhesiveor sealing compound be accurately controlled during the sealingoperation to assure its proper spreading and to reduce the quantityrequired to a minimum. The amount of adhesive used is a very importantfactor as it is an extremely expensive product in relation to theoverall cost production of a container, and unless it can be used invery small quantities uneconomical production cost results.

It has been found that the amount of adhesive used in order to maintaina proper seal need only be a light film. However, such a light film willbe effective only when the adhesive is properly applied and when theseal will not be subjected to rupturing through change in pressure orthrough shock.

Another reason for ineffective sealing of fibre bodied containers, wherea theoretically effective minimum quantity of adhesive is employed, isthe presence of a small circumferential burr on the inner peripheraledge of the containers, this burr being caused by the cutting toolduring the winding operation. The burr, though small, prevents theadhesive from effectively covering the surface adjacent the mouth wheresealing is to be accomplished by allowing the adhesive to flow over theend of the body by gravity.

The object of the present invention is to provide a method of sealingwhich overcomes the foregoing difficulties and which utilizes a minimumamount of adhesive, and wherein the closure is so constructed thatcontrol of the adhesive is assured during the sealing operation andwherein the seal will not be subjected to rupturing due to changes inpressure or due to shock.

These and other objects will become apparent from the followingdescription when read with Fig. 1;

Referring to the drawings, the closure A (Fig. 1)

isparticularly adapted for sealing the fibre container body B (Fig. 8)which body comprises a member ID made, for example, by convolutelywinding a strip of chipboard until desired strength is obtained andhaving a suitable lining l2 to render the body moisture or liquid proof.The lining may be a suitable coating material either applied in liquidform and permitted to dry, or in sheet form suitably secured to theinner surface of the body. Due to the cutting action in the making ofthe containers, a burr l5 (Fig. 3) is formed on the inner peripheraledge which burr has, as previously stated, heretofore prevented theobtaining of a proper seal with a theoretically effective minimum amountof adhesive.

Herein the closure A is made of metal and comprises a generally circularbody part [4 and a circumferential bottom facing sealing channel orgroove [6 secured to the end of the body part l4 and within which theend of the body B is received and secured. More specifically, the bodypart [4 includes a central disk or concave flexible diaphragm l8 havinga cylindrical supporting wall 20 depending from the peripheral edgethereof, and a spacing member or ring 22 extending laterally from thelower edge of wall 20. The spacing member 22 provides a support for theinner cylindrical sealing wall 24 of the channel I6, this wall extendingvertically to the same height as wall 20 and paralleling same, thecircumference of the wall 24 being less than the inside circumference ofthe body B. Extending laterally outward from the upper edge of wall 24is a connecting web 25 having an outer circumference larger thanthe,inside circumference of the body B, but smaller than the outsidecircumference of the body B. Depending from the outer arrears cumferencelarger than the outside circumference of the body B.

To complete the closure, the ceiling of channel l6 has a band ofadhesive 30 therein, the band extending to a level approximating thepoint where the circumference of the flange 26 is equal to the outsidecircumference of the container body B. The adhesive must be suflicientlyviscous not to flow when handling, and the type used will depend uponthe article to be packaged and the manner in which the closures are fedonto the body during the sealing operation. For example, when oil is tobe packaged, the adhesive must be insoluble in oil, whereas this is notessential for powdered products, though in each instance a liquid ormoisture proof seal is necessary.

With the closure A so made, it will be seen that upon applying it to theend of the body B, the body end will move readily into the channel I6(Fig. 3) until its outer edge contacts the inner surface of; the flange26 (Fig. 4) at a point above the lower edge and approximately at thelevel of the adhesive 30, the inner wall 24 being spaced from the innerwall of the body B and fitting loosely Within same. Thereafter, as theclosure is subjected to downward pressure, the adhesive is displacedinwardly and against the inner wall 24 (Fig. 5) outward displacementbeing prevented by the damming action of the contacting edge of the bodyand the inner face of flange 26. By displacing the adhesive inwardly, itis forced or sprayed across the burr I 5 and onto the wall 24 to form aband 32 (Fig. 5) of adhesive which will tend to flow down and spreadevenly over the surface of the wall 24.

To complete the seal, the wall 24 (Figs. 6 and '7) is then offset orflowed against the body either by seaming wheels or expanding chuckswhereby the adhesive is evenly spread to provide a film of adhesivebetween wall 24 and the inner wall of the body B, this f lm extendingslightly beyond the wall, as at 30 in Fig. 7. Simultaneously, theflange, 26 is brought into contact with the outer face of the b dy a ies d. t o r pheral dg pegged i o the. bo y. as at 29.

I h s been ound tha th film s sufiicient to maintain the proper seal ifit completely covers the area between the wall 24 and the inner surfaceof the body contacted by the wall 24 and, as a result, a minimumofadhesive or sealing compound is required. The amount can readily bedetermined since the area to be covered is known inasmuch as it isequivalent to the surface area of wall 24. Because of this, the cost isreduced to a minimum and no excess adhesive is, used. 7 v

In addition to providin a seal, it is also essential that the seal beundisturbed due to pressure changes within the container. Such pressurechanges most frequently result when heat sealingis used, that is, whenthe adhesive 30 is a type which is normally set but is rendered fluid orsemi-fluid by application of heat. As previously stated, the centraldiaphragm I8 is flexible, this being accomplished by making the closureof extremely light metal, the thickness being exa gerated in thedrawings. As a result, when pressure builds up within thecontai'ner, thediaphragm will tend to flex and flatten without placing any strain onwall 24. In the preferred embodiment, the possibility of strain isfurther prevented by the provision of the supporting wall 2 0 andspacingrin 22. With this arrangement, it be seen'tnamwhen thediaphragm'tends to 4 flatten, wall 20 will flex toward wall 24 about thering 22 as a fulcrum and thus no strain is placed on wall 24 tending topull it from the body.

Likewise, if the container is dropped 'or subjected to other shock, theseal will not be broken by radial folds which form in the closures undersuch conditions. In the present closure, the fold will start at the topof wall 20 and move in across the diaphragm, the walls of the channelremaining undisturbed and the seal unbroken.

In addition to the other advantages, the use of an extremely light metalsaves considerable weight which reflects savings in the cost ofproduction as well as in shipping costs, and by raising the diaphragm tothe level shown by use of wall 20 substantially full capacity of thebody is retained.

The present closure is also particularly adapted for rapid feeding as itcan be stacked without nesting. As seen in Fig. 9, because of theparallelism of wall 26 and wall 24, there is provided a top facinggroove 21, the peripheral upper edges of which act as a seat for thespacing ring 22 upon which the latter will rest with sufiicient contactto retain the closures seated and yet permit one to be readily slid awayfrom the other. This is a decided advantage in the capping operationfollowing filling, for, with present production lines, the containersmay be filled at the rate of one hundred and sixty to one hundred andeighty a minute. It will also be noted that the groove 21 provides spacefor reception of an expanding chuck.

In Fig. 10, there is shown a closure similar to that shown in thepreceding figures insofar as the method of sealing is concerned. Theclosure has a body part 55) and a sealing groove 16. The body part herecomprises a circular flexible disk 52 and, supported on its outerperipheral edge and extending vertically therefrom, is the inner wall 24of the sealing groove Hi, this groove being identical to that in thefirst embodiment with like parts having like numbers. The seal is formedby the same method as that described.

Although the closures have been described as circular, it is apparentthat they could be of oval shape and the same advantages obtained.Therefore, the terms circular and circumferential as used herein are -tobe interpreted as including oval or elliptical closures, for it isobvious that wherever circumference has been used in the description,the same results are obtainable by measuring the circumference of anoval or ellipse.

I claim as my invention:

1. The method of sealing a fibre container body with a closure having adownwardly facing sealing channel with an inner generaly cylindricalwall and a downwardly and outwardly tapering outer flange, said wall andflange being of substantially greater depth than the thickness of thebody wall, which comprises placing an ad'-.

hesive in the channel so as to form a band of adhesive in the ceilingthereof, positioning the closure upon the end of the fibre body with theouter flange resting between its extremities upon the outer edge of thebody wall with the inner wall being spaced inwardly from the body wall,pressing the closure and body towards each other for moving the end ofthe body along the outer flange and into the channel for forcing aportion of the adhesive into the space between the body wall and theinner wall of the closure channel, maintaining pressing engagementduring said movement between the outer edge of the body wall and theouter flange for retaining the adhesive against outward movement, andfinally outwardly expanding the inner wall and inwardly moving the outerflange into gripping engagement with the body wall.

2. The method of sealing a fibre container body with a closure having aninverted channel of substantially greater depth than the thickness ofthe fibre container body wall, said channel including an inner generallycylindrical wall of lesser circumference than the inside circumferenceof the body and a downwardly and outwardly tapering fiange having acircumference,

between its extremities corresponding to the circumference of the outeredge of the body wall, which comprises providing a band of adhesive inthe ceiling of the channel to a level not extending outwardly beyond theouter edge of the body wall, placing the closure upon the end of thebody with the outer flange resting upon the outer edge of the body wallwith the inner wall spaced inwardly from the body wall, pressing thebody and closure towards each other for forcing the end of the bodyalong the outer flange and into the channel for forcing a portion of theadhesive onto the inner surface of the body, and then expanding theinner wall of the closure against the body while simultaneously bringingthe outer flange of the closure into contact with the outer surface ofthe body.

3. A method of sealing a metal closure to an end of a tubular fibrecontainer body, said closure having a peripheral channel provided withan inner generally cylindrical wall and an outer wall divergingtherefrom, said inner and outer walls being of substantially greaterdepth than the thickness of the body wall, the base of the outer wallbeing of less diameter than the outside diameter of the body and theinner wall being of less diameter than the inside diameter of the body,which comprises placing a predetermined amount of sealing compound inthe base of the channel, positioning the outer wall of the channelagainst the end of the body to prevent the passage of sealing compoundtherebetween,pressing the closure onto the body for forcing a portion ofthe compound into space between the inside surface of the body and theinner wall of the channel, and finally moving the inner and outer wallsof the closure into pressing engagement with the body.

ROBERT S. CONDON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,230,987 Karl Feb. 4, 19412,238,056 Hothersall Apr. 15, 1941 2,413, 449 Hatch Dec. 31, 1946FOREIGN PATENTS Number Country Date 376,960 Italy Dec. 1, 1939

